Highly integrated novel technologies, for example in the field of communications, in transport, in medicine, in microelectronics and in microsystems technology, and for the effective generation, storage and utilization of energy, require materials having novel, precisely defined properties and optimized functionalities. Plastics have a high potential for this purpose, since they can be tailored for a multitude of applications and can also themselves assume functions.
Current methods are attempting to unlock this potential by the development of functional polymers and nanostructured (hybrid) materials. Their aim is the exact adjustment of the architecture, functionality, self-assembly and nanostructure of plastics.
It is generally desirable for integration of function that the materials can be incorporated into highly integrated components and complex material composites with the desired functionality and morphology in a reproducible manner, with long-term stability in terms of their function, and in an environmentally compatible and inexpensive manner.
The methods known from the prior art for functionalizing the plastic in a component or even selectively just the surface thereof in a desirable manner very predominantly follow the following strategies:
Firstly, functionality is achieved by adding functional additives and fillers to the plastic. For example, it is possible to achieve isotropic and anisotropic electrical conductivity, and in some cases even thermal conductivity, by incorporating conductive blacks, carbon nanotubes or graphenes into the plastic. A drawback of this approach is that the properties of the bulk material are altered with increasing additive or filler content in the course of incorporation of the additives or fillers.
An alternative is to proceed from an already functionalized monomer unit, which is homo- or copolymerized in order to obtain a functionalized plastic. A drawback of this approach is that the functionality cannot be restricted selectively to a particular region of the plastic, such that the plastic has a substantially homogeneous profile of properties, meaning that there is no difference in the properties of the bulk material and the surface. A further drawback is that functionalized monomer units typically have to be synthesized in a complex manner, and the use thereof in large amounts is therefore uneconomic.
Secondly, plastics having functionalized surfaces are produced, for example, via coating methods by application of a new material layer to an existing bulk material or by material removal methods, wherein material is removed from the surface. A drawback of the coating methods is that the newly applied material layers frequently adhere to the bulk material to an insufficient degree and the functionalized surface thus obtained does not have sufficient long-term stability. The exclusive aim of functionalization by material removal methods is usually a change in the surface structure, and hence is limited in terms of application.
The methods known from the prior art for producing plastics having a functionalized surface accordingly have inadequate efficiency and/or lead to functionalized surfaces having inadequate long-term stability. Against the background of the prior art, there is a need for efficient processes for producing plastics having a functionalized surface which can be functionalized in a controlled manner without loss of the bulk properties, wherein functionalized surfaces having prolonged stability are obtained. The processes described to date in the prior art for producing plastics having a functionalized surface either proceed from existing plastics which are subsequently modified or coated by a wide variety of different surface methods or the self-assembly capacity of materials to form specific heterogeneous structures is utilized.
WO 2015/166983 discloses the use of isocyanurate polymers for encapsulating LEDs. A two-stage process of firstly trimerizing an oligomeric polyisocyanate to provide a bulk polyisocyanurate material and subsequently contacting the surface of the bulk material with a functionalizing agent is not disclosed.
U.S. Pat. No. 6,133,397 only discloses coatings made by trimerizing oligomeric polyisocyanates. It does not disclose a two-step process as disclosed by the present application.
The problem addressed by the present invention was therefore that of providing a novel process for producing polyisocyanurate plastics having a functionalized surface, wherein the functionalized surface is notable for excellent adhesion and stability.
This problem is solved in accordance with the invention by the process specified in Claim 1 and the polyisocyanurate plastic specified in Claim 16.
Advantageous configurations of the invention are specified in the dependent claims and are elucidated in detail hereinafter, as is the general idea of the invention.